Radio wave reflector, method for manufacturing radio wave reflector, radio wave reflecting structure, radio wave reflecting system, and radio wave reflecting device

Abstract

The invention provides a radio wave reflector capable of reflecting radio waves in a wide space range, a method for manufacturing the radio wave reflector, a radio wave reflecting structure, a radio wave reflecting system, and a radio wave reflecting device. This radio wave reflector (10) has a reflecting surface that reflects radio waves, and the reflecting surface (11d) has a curved surface that protrudes toward the side on which the radio waves are incident or reflected.

Description

Technical Field

[0001] The present invention relates to a radio wave reflector for reflecting radio waves, a method for manufacturing the radio wave reflector, a radio wave reflection structure, a radio wave reflection system, and a radio wave reflection device. Background Art

[0002] In mobile phones and wireless communications, radio waves in a frequency band of 2 GHz or more and about 300 GHz or less, called centimeter waves or millimeter waves, are used. Such radio waves with short wavelengths have strong straightness and are difficult to bypass even when there are obstacles. Therefore, in order to make the radio waves reach a wider range, a reflector is provided on the surfaces of buildings such as the walls, floor surfaces, ceilings, and columns of buildings (hereinafter referred to as "walls, etc."). For example, Patent Document 1 proposes a communication system in which a monopole antenna and a metal reflector for reflecting radio waves are arranged in the under-floor space of a house. In Patent Document 1, while diffusing the radio waves radiated from the monopole antenna to the under-floor space through the reflector, leakage of radio waves from the under-floor space to the outside of the room (house) or absorption of radio waves by the floor part of the building are prevented.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2010-258514 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] Generally, when a metal reflector reflects radio waves, the reflection intensity of the reflected wave is maximum at normal reflection, and the reflection intensity of the reflected wave deviating from the normal reflection direction becomes smaller. If the receiver is located at a position deviating from the normal reflection direction, the receiver cannot receive radio waves with a sufficient intensity for practical use. Especially when the reflecting surface of the metal reflector is flat, the reflection intensity of the reflected wave in the normal reflection direction is very large, and the reflection intensity of the reflected wave slightly deviating from the normal reflection direction is very small. Therefore, if the receiver is located at a position slightly deviating from the normal reflection direction, sometimes sufficient radio waves cannot be obtained.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a radio wave reflector, a method for manufacturing the radio wave reflector, and a radio wave reflection system that can reflect radio waves in a wider range of space.

[0009] Technical Means for Solving the Problem

[0010] To achieve the above object, the present invention includes the following.

[0011] Item 1. A radio wave reflector having a reflecting surface for reflecting radio waves, wherein,

[0012] The reflecting surface is a curved surface that bulges toward the side where the radio wave is incident or reflected.

[0013] Item 2. The radio wave reflector according to Item 1, wherein

[0014] The curvature 1 / r of the reflecting surface satisfies 0 (1 / m) < 1 / r ≤ 7.85 (1 / m).

[0015] Item 3. The radio wave reflector according to Item 1, wherein

[0016] The curvature 1 / r of the reflecting surface satisfies 5.00 (1 / m) < 1 / r ≤ 7.85 (1 / m).

[0017] Item 4. The radio wave reflector according to any one of Items 1 to 3, comprising:

[0018] A conductive layer, which contains a conductor and forms the reflecting surface;

[0019] A base material layer, which contains a base material for holding the conductive layer;

[0020] A protective layer, which contains a protective material for protecting the conductive layer; and

[0021] An adhesive layer, which contains an adhesive material for bonding the conductive layer and the layer containing the protective material,

[0022] The radio wave reflector is laminated in the order of the base material layer, the conductive layer, the adhesive layer, and the protective layer.

[0023] Item 5. The radio wave reflector according to Item 4, wherein

[0024] The flexural modulus is 0.05 GPa or more and 4 GPa or less.

[0025] Item 6. The radio wave reflector according to any one of Items 1 to 5, further comprising a holding member for holding the reflecting surface.

[0026] Item 7. A method for manufacturing the radio wave reflector according to any one of Items 1 to 5, comprising:

[0027] A step of bending the reflecting surface into a curved surface that bulges toward the side where the radio wave is incident or reflected when installing it on an object to be installed.

[0028] Item 8. A method for manufacturing the radio wave reflector according to Item 6, comprising:

[0029] A step of holding the curved surface formed by bulging the reflecting surface toward the side where the radio wave is incident or reflected through the holding member before installing it on an object to be installed.

[0030] Item 9. A radio wave reflecting structure, comprising:

[0031] The radio wave reflector according to any one of Items 1 to 6; and

[0032] An installation object for installing the radio wave reflector.

[0033] Item 10. A radio wave reflection system, comprising:

[0034] A transmitter that transmits radio waves;

[0035] The radio wave reflector according to any one of Items 1 to 6, which reflects the radio waves transmitted from the transmitter;

[0036] A receiver that receives the radio waves reflected by the radio wave reflector; and

[0037] A rotational position adjustment device that is provided on the radio wave reflector and rotates the radio wave reflector.

[0038] Item 11. The radio wave reflection system according to Item 10, wherein

[0039] The rotational position adjustment device rotates the radio wave reflector around the protruding vertex of the radio wave reflector when viewed from a plane parallel to the plane including the incident direction and the reflection direction of the radio wave to the reflection surface,

[0040] When the rotation angle of the position of the radio wave reflector at the time of directly reflecting the radio waves transmitted from the transmitter to the receiver is set to 0 degrees, the clockwise rotation direction is set to the + direction, and the counterclockwise rotation direction is set to the - direction, the position of the radio wave reflector that can be adjusted by the rotational position adjustment device is within the range where the rotation angle is -90 degrees or more and +90 degrees or less.

[0041] Item 12. The radio wave reflection system according to Item 11, wherein

[0042] The curvature 1 / r is 4.73 (1 / m),

[0043] When the radio wave reflector is in the position within the range of the rotation angle of -83 degrees or more and +83 degrees or less, the receiver receives radio waves of -95 dB or more.

[0044] Item 13. A radio wave reflection device, comprising:

[0045] The radio wave reflector according to any one of Items 1 to 6; and

[0046] A rotational position adjustment device that is provided on the radio wave reflector and rotates the radio wave reflector.

[0047] Advantages of the Invention

[0048] According to the present invention, a radio wave reflector that reflects radio waves over a relatively wide range of space, a method for manufacturing the radio wave reflector, and a radio wave reflection system can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a diagram for explaining a radio wave reflection system of a radio wave reflector having an embodiment of the present invention.

[0050] Figure 2 is a diagram showing a schematic configuration of the radio wave reflector. (A) is a cross-sectional view taken along the X1-X1 line of (B), and (B) is a perspective view.

[0051] Figure 3 (A) is a cross-sectional view taken along the X2-X2 line of (B) showing a schematic configuration of another embodiment of the radio wave reflector. (B) is a perspective view, and (C) is a perspective view showing another embodiment.

[0052] Figure 4 is a cross-sectional view taken along the B-B line when the radio wave reflector is placed on a plane without being bent Figure 5 of.

[0053] Figure 5 shows a schematic configuration of the entire radio wave reflector when the radio wave reflector is placed on a plane without being bent. (A) is a top view, and (B) is an enlarged view of part A of (A).

[0054] Figure 6 (A) to (E) are cross-sectional views showing other examples of the arrangement pattern of the conductor.

[0055] Figure 7 (A) is a cross-sectional view showing another example of the conductor, and (B) is an enlarged view of part D of (A).

[0056] Figure 8 (A) is a cross-sectional view showing another example of the conductor, and (B) is an enlarged view of part D of (A).

[0057] Figure 9 is a cross-sectional view showing a schematic configuration when the radio wave reflector is placed on a plane without being bent in the radio wave reflector of another embodiment.

[0058] Figure 10 is a cross-sectional view showing a schematic configuration when the radio wave reflector is placed on a plane without being bent in the radio wave reflector of another embodiment.

[0059] Figure 11 ​​​​​​​​​​​(A) is an explanatory diagram showing an application example of a building material to a building, and (B) is a top view showing an application example to an interior.

[0060] Figure 12 Explanatory diagram of the rotation angle of the radio wave reflector.

[0061] Figure 13 is a diagram showing the measurement results of Comparative Example 1.

[0062] Figure 14 is a diagram showing the measurement results of Example 1.

[0063] Figure 15 is a diagram showing the measurement results of Example 2.

[0064] Figure 16 is a diagram showing the measurement results of Example 3.

[0065] Figure 17 is a diagram showing the measurement results of Example 4.

[0066] Figure 18 is an explanatory diagram of the rotation angle of the receiver.

[0067] Figure 19 is a diagram showing the measurement results of Examples 5 to 10 and Comparative Example 2.

[0068] Figure 20 is a diagram showing the measurement results of Examples 5 to 10 and Comparative Example 2. Detailed implementation mode

[0069] (Overall configuration)

[0070] The embodiments of the present invention will be described with reference to the accompanying drawings. As Figure 1 shown, a radio wave reflection system 100 including a radio wave reflector 10 of the present invention is used to reflect radio waves transmitted from a transmitter 20 and propagate them to a receiver 21. The radio wave reflection system 100 includes: a transmitter 20 that transmits radio waves; a radio wave reflector 10 that has a reflection surface 11d and reflects radio waves transmitted from the transmitter 20; and a receiver 21 that receives radio waves reflected by the radio wave reflector 10. The radio wave reflection system 100 may further include a rotation position adjustment device 50 provided on the radio wave reflector 10 to rotate the radio wave reflector 11 ( Figure 12 ​​​​​​​​​)). The transmitter 20 is a communication device such as a device with a transmitting antenna capable of transmitting radio waves. The receiving unit 21 is a communication device with a receiving antenna capable of receiving radio waves. As the receiving unit 21, for example, a smartphone, a mobile phone, a tablet computer, a notebook PC, a portable game console, a repeater, a broadcast, a television, etc. can be cited. In addition, the radio wave reflector 10 and the installation object 24 on which the radio wave reflector 10 is installed constitute a radio wave reflection structure 101.

[0071] Referring Figure 1 For the description, specular reflection means that when the radio wave transmitted by the transmitter 20 is reflected by the radio wave reflector 10, the incident angle θ1 of the incident wave is equal to the reflection angle θ2 of the reflected wave. The incident angle θ1 is the angle formed by the incident wave advancing in the incident direction ( Figure 1 (indicated by the arrow A1 in.) and the normal 22 of the reflection surface 11d of the radio wave reflector 10, and the reflection angle θ2 is the angle formed by the reflected wave advancing in the reflection direction ( Figure 1 (indicated by the arrow A2 in.) and the normal 22 of the reflection surface 11d. The normal 22 is a straight line orthogonal to the tangent 23 (or tangent plane) at the reflection point 11a of the reflection surface 11d. The intensity of the reflected wave is also referred to as the "reflection intensity". The "specular reflection intensity" is the reflection intensity as the intensity of the reflected radio wave, which is the intensity of the reflected wave when the incident wave undergoes specular reflection. The "specular reflection direction" is the traveling direction of the reflected wave when the radio wave undergoes specular reflection. The "specular reflection angle" is the incident angle θ1 of the incident wave and the reflection angle θ2 of the reflected wave during specular reflection. The frequency of the radio wave transmitted by the transmitter 20 is 2 GHz or more and 300 GHz or less.

[0072] The radio wave reflector 10 has a reflection surface 11d for reflecting radio waves. As Figure 1 shown, the reflection surface 11d is a curved surface that protrudes toward the side where the radio wave is incident or reflected in the state when it is installed on an installation object 24 such as a wall, that is, in the so-called installation structure.

[0073] The radio wave reflector 10 may be composed only of the radio wave reflection material 11, or may be composed of the radio wave reflection material 11 and other components such as a holding member 40 (described below). In Figure 2 (A), Figure 2 (B) shown in the example, the radio wave reflector 10 is composed only of the radio wave reflection material 11.

[0074] As Figure 4As shown, the radio wave reflecting material 11 is formed by laminating a conductive layer 16 containing a conductor 12 and a base material layer 13 containing a base material that holds the conductive layer 16, as described in detail below. The reflection surface 11d refers to the surface on the side (also referred to as the "outer side") where the radio wave is incident or reflected, which includes the conductive layer 16 containing the conductor 12 in the cross-section of the imaginary plane along the incident direction of the incident wave based on the transmitter 20 and the reflection direction in which the reflected wave received by the receiver 21 advances. Hereinafter, the imaginary plane including the incident direction of the incident wave based on the transmitter 20 and the reflection direction in which the reflected wave received by the receiver 21 advances is also referred to as the "imaginary plane including the incident direction and the reflection direction".

[0075] In the present embodiment, the radio wave reflector 10 is bent in a manner that bulges toward the side where the radio wave is incident or reflected in the cross-section of the imaginary plane including the incident direction and the reflection direction, or when viewed from a plane parallel to this imaginary plane. Therefore, the reflection surface 11d included in the radio wave reflecting material 11 also becomes a curved surface that bulges toward the side where the radio wave is incident or reflected. The curvature is set based on this reflection surface 11d.

[0076] In the case where the conductive layer 16 is composed of, for example, a thin-film-like conductor 12 and a conductor 12 in the form of a metal plate, the reflection surface 11d refers to the outer surface of the thin film or the metal plate. In the case where the conductive layer 16 includes, for example, a linear conductor 12 and a non-conductive region 12a surrounded by the conductor 12, the reflection surface 11d refers to the surface including the outer side of the conductor 12 and the surface of the non-conductive region 12a.

[0077] It should be noted that the radio wave reflecting material 11 may also have, on the surface of the conductive layer 16 opposite to the surface where the base material layer 13 is provided: a protective layer 15 containing a protective material for protecting the conductive layer 16; and an adhesive layer 14 containing an adhesive material for bonding the conductive layer 16 and the protective layer 15 between the conductive layer 16 and the protective layer 15. That is, the radio wave reflecting material 11 may be laminated with the base material layer 13, the conductive layer 16, the adhesive layer 14, and the protective layer 15 in sequence. The side where the protective layer 15 is provided ( Figure 4 the upper side) becomes the side (outer side) where the radio wave is incident or reflected. When the thicknesses of the adhesive layer 14 and the protective layer 15 are constant and the outer surface of the protective layer 15 is parallel to the outer surface of the conductive layer 16, the curvature of the reflection surface 11d is the same as the curvature of the outer surface of the protective layer 15.

[0078] It should be noted that in Figure 1 、 Figure 2 、 Figure 3 、 Figure 12 、 Figure 18 For the sake of convenience in explanation, the symbols of the reflection surface 11d and the vertex 11c below are marked on the outermost surface of the radio wave reflecting material 11.

[0079] The curvature 1 / r of the reflecting surface 11d of the radio wave reflector 10 is preferably set such that 0 (1 / m) < 1 / r ≤ 7.85 (1 / m). In the present embodiment, the curvature 1 / r of the reflecting surface 11d of the radio wave reflector 10 is defined as the reciprocal of the radius of curvature r (m) when the curve of the reflecting surface 11d of the radio wave reflector 10 is approximated as an arc at any point on the reflecting surface 11d represented as a curve in a cross-section along the imaginary plane including the incident direction and the reflection direction.

[0080] The curvature 1 / r of the reflecting surface 11d is preferably set such that 5.00 (1 / m) < 1 / r ≤ 7.85 (1 / m), and more preferably set such that 5.25 (1 / m) < 1 / r ≤ 7.81 (1 / m). In Evaluation Test B below, in the case of both frequencies of 4.85 GHz and 28 GHz, the range of this curvature is set based on Examples 9 and 10 with an angular range of 150 degrees or more. If the curvature of the reflecting surface 11d is within this range, radio waves can be reflected within a relatively wide range in space.

[0081] As described above, the radio wave reflecting material 11 of the radio wave reflector 10 includes a base material layer 13, a conductive layer 16, an adhesive layer 14, and a protective layer 15. When these are laminated in this order, the flexural modulus of elasticity of the radio wave reflecting material 11 is preferably 0.05 GPa or more and 4 GPa or less. The flexural modulus of elasticity is a value indicating how much bending stress can be borne and is defined by JIS K7171. By setting the flexural modulus of elasticity within the above range, the radio wave reflecting material 11 has flexibility and can bend the radio wave reflector 10 within the range of the curvature 1 / r without breaking the radio wave reflecting material 11. The flexural modulus of elasticity is measured based on JIS K7171.

[0082] The radio wave reflecting material 11 preferably has a Young's modulus of 0.01 GPa or more and 80 GPa or less. The Young's modulus refers to the elastic modulus when a solid is stretched by applying tension in one direction and is also called the tensile elastic modulus, which is defined by JIS K7161-2014. By setting the Young's modulus within the above range, the radio wave reflecting material 11 is easily deformed and can bend the radio wave reflecting material 11 within the range of the curvature 1 / r without breaking the radio wave reflector 10. The Young's modulus is measured based on JIS K7127-1999.

[0083] The radio wave reflector 10 only needs to have a curved surface, i.e., the reflecting surface 11d, that protrudes toward the side where radio waves are incident or reflected when it is installed on an installation object 24 such as a wall, and the shape before being installed on the installation object 24 is arbitrary. A method for manufacturing the radio wave reflector 10 is described as follows. First, a radio wave reflecting material 11 is prepared as a sheet-like component. Then, when it is installed on an installation object 24 such as a wall, the radio wave reflecting material 11 (sheet-like component) is bent into a curved surface that protrudes toward the side where radio waves are incident or reflected. Thus, the radio wave reflector 10 is manufactured. The manufactured radio wave reflector 10 is installed on the installation object 24 through an installation unit such as an adhesive. That is, before and after being installed on the installation object 24, the radio wave reflector 10 has the same composition but different shapes.

[0084] Figure 2 (A), Figure 2 (B) shows examples of the radio wave reflector 10. Figure 2 (A), Figure 2 The radio wave reflector 10 in (A) and (B) is composed of a radio wave reflecting material 11. The radio wave reflecting material 11 is a rectangular sheet-like component in the state before being installed on the installation object 24. The radio wave reflecting material 11 is bent in such a way that the opposing side edges 11b approach each other, thereby forming the radio wave reflector 10.

[0085] The formed radio wave reflector 10, i.e., the radio wave reflector 10 formed only by the radio wave reflecting material 11, as shown in Figure 2 (A), has a semicircular cross-sectional shape along the imaginary plane including the incident direction and the reflection direction, i.e., along the Figure 2 X1-X1 line shown in (B), and protrudes toward the side where radio waves are incident or reflected.

[0086] The direction orthogonal to the imaginary plane including the incident direction and the reflection direction is defined as the up-down direction, and the direction including the two opposing side edges 11b on the imaginary plane including the incident direction and the reflection direction is defined as the left-right direction. As shown in Figure 2 (A), the radio wave reflector 10 is line-symmetric at the central position in the left-right direction. The distance between the opposing side edges 11b (the length between the inner surfaces of the two side edges 11b) L11 is also referred to as the "bottom width L11" and is appropriately set according to the size, reflection intensity, etc. of the radio wave reflector 10.

[0087] The protruding curved surface has a vertex 11c. The convex vertex 11c refers to the point that protrudes most toward the side where radio waves are incident or reflected with respect to the base end of the reflecting surface 11d in the cross-section along the imaginary plane including the incident direction and the reflection direction. In the example of Figure 2 (A), Figure 2(A)'s upper side is the side where radio waves are incident or reflected. The vertex 11c is the point that protrudes from the side edge 11b as the base end to the uppermost side. The vertex 11c is the point that is orthogonal to the left - right direction and intersects with the imaginary line passing through the central point of the width L11 of the bottom. As Figure 2 shown in (B), the vertex 11c extends in the up - down direction.

[0088] It should be noted that the vertex 11c of the radio - wave reflector 10 can also be bent in a way that extends along a direction inclined with respect to the up - down direction or the left - right direction.

[0089] The convex curved surface refers to a curved surface whose central part protrudes to one side. For example, in the cross - section along the imaginary plane containing the incident direction and the reflected direction, it can be a semi - circular shape, a semi - elliptical shape, or any shape along a conic curve. In addition, the overall shape can also be a hemispherical shape or a semi - ellipsoidal shape. The sheet - like component means a component whose longitudinal or transverse length of one side in the top - view is much larger than the thickness. For example, it means that the longitudinal or transverse length is 10 times or more of the thickness.

[0090] In this example, when it is in circulation in the market, that is, before being installed on a wall or the like, the radio - wave reflection material 11 is a rectangular sheet - like component, but this sheet - like component can also be wound into a roll shape. In addition, a filling material containing resin or the like can be filled in the space generated between the convex - shaped radio - wave reflector 10 and the installation object 24 such as a wall. Furthermore, Figure 3 the holding component 40 (described below) shown in the figure can be installed on the installation object 24 such as a wall first, and the radio - wave reflection material 11 can be installed on the convex outer peripheral surface 40a of the holding component 40.

[0091] In addition, as Figure 3 (A), Figure 3 (B) shows, the radio - wave reflector 10 can also include the radio - wave reflection material 11 and the holding component 40 that holds the curved surface of the reflection surface 11d of the radio - wave reflection material 11. In Figure 3 (A), Figure 3 (B) example, the holding component 40 is a base with an outer peripheral surface 40a whose cross - section is convex. The convex shape of the outer peripheral surface 40a of the base corresponds to the curved surface of the reflection surface 11d of the radio - wave reflection material 10. By installing the radio - wave reflection material 11 on the outer peripheral surface 40a of the base, a radio - wave reflector 10 is formed that holds the curved surface protruding on the side where radio waves are incident or reflected to the reflection surface 11d. In one example, the base has a semi - cylindrical installation portion 42 provided on one surface of the plate - shaped base body 41, and the radio - wave reflection material 11 is installed on the outer peripheral surface 40a of the installation portion 42.

[0092] However, the pedestal for holding the component 40 is not limited to this. As long as it has an outer peripheral surface 40a with a convex shape corresponding to the shape of the cross-section of the curved surface of the reflection surface 11d of the radio wave reflection material 11 in such a way that the curved surface of the reflection surface 11d can be held, it can also be a component with an arbitrary shape such as a columnar shape or a bent plate shape. In addition, the holding component 40 does not need to be a pedestal. For example, a convex-shaped layer without flexibility can also be provided on one surface of the radio wave reflection material 11 as the holding component 40 to hold the curved surface of the reflection surface 11d of the radio wave reflection material 11. In addition, the holding component 40 can also serve as at least one of the base material layer 13, the adhesive layer 14, and the protective layer 15 included in the radio wave reflection material 11. In this case, the base material layer 13, the adhesive layer 14, and the protective layer 15 are formed into a convex shape without flexibility, so as to hold the curved surface of the reflection surface 11d as a whole for the radio wave reflector 10.

[0093] In Figure 3 (A), Figure 3 (B) In the manufacturing method of the radio wave reflector 10 shown, before installing on the installation object 24, it includes the step of holding the reflection surface 11d of the radio wave reflection material 11 by the holding component 40, that is, holding the curved surface protruding toward the side where radio waves are incident or reflected. Moreover, the radio wave reflection material 11 and the holding component 40 are integrated into the radio wave reflector 10 and installed on the installation object 24.

[0094] In Figure 3 (B) In the example, the radio wave reflection material 11 is bent with the protruding vertex 11c in the vertical direction and installed on the outer peripheral surface 40a of the holding component 40. However, it is not limited to this. The vertex 11c can also be along the left-right direction, and the vertex 11c can also be installed in a direction inclined with respect to the vertical direction or the left-right direction.

[0095] The radio wave reflection material 11 can be, for example, as Figure 3 (C) shown, in a hemispherical shape or a semi-elliptical shape. It should be noted that in Figure 3 (C), the base end of the radio wave reflection material 11 is installed on the holding component 40.

[0096] In the radio wave reflection system 100 of the present embodiment, as Figure 12 shown, a rotation position adjustment device 50 such as a turntable can also be provided on the radio wave reflector 10. The radio wave reflector 10 and the rotation position adjustment device 50 constitute a radio wave reflection device 102. The rotation position adjustment device 50 can make the radio wave reflector 10 rotate clockwise and counterclockwise around the vertex 11c when viewed from the cross-section along the imaginary plane including the incident direction and the reflection direction, that is, in the Figure 12 top view shown. As Figure 1As shown, when the radio wave reflector 10 reflects the radio wave transmitted from the transmitter 20 directly towards the receiver 21, the radio wave reflector 10 is at the position where the rotation angle is 0 degrees. The clockwise rotation direction is set as the + direction, and the counterclockwise rotation direction is set as the - direction. At this time, the position of the radio wave reflector 10 that can be adjusted by the rotation position adjusting device 50, in a top view, the rotation angle can be in the range of -90 degrees or more and +90 degrees or less. Specifically, the curvature 1 / r of the reflecting surface 11d of the radio wave reflector 10 is 4.73 (1 / m). When the radio wave reflector 10 is at the position within the range of the rotation angle from -83 degrees to +83 degrees, the receiver 21 can receive radio waves of -95 dB or more.

[0097] The applicant has found that by having the reflecting surface 11d of the radio wave reflector 10 be a curved surface that bulges towards the side where the radio wave is incident or reflected, compared with the conventional case where the reflecting surface 11d of the radio wave reflector 10 is a flat surface, the radio wave reflector 10 can reflect radio waves with practical sufficient intensity within a relatively wide range in space. Therefore, in the imaginary plane including the incident direction of the incident wave of the radio wave and the reflecting direction of the directly reflected wave, even when the receiver 21 is located at a position deviated from the directly reflecting direction of the radio wave, the receiver 21 can receive radio waves with sufficient intensity.

[0098] When the position of the receiver 21 is predetermined, in the imaginary plane including the incident direction of the incident wave and the reflecting direction of the reflected wave, by installing the radio wave reflector 10 at the position where the rotation angle is 0 degrees, the receiver 21 can receive radio waves with practical intensity. However, it is difficult to install the radio wave reflector 10 strictly at the position where the rotation angle is 0 degrees. For example, due to the bending or inclination of the installation object 24 such as a wall, the radio wave reflector 10 deviates from the position where the rotation angle is 0 degrees, and the radio wave reflector 10 is sometimes installed at a position rotated clockwise or counterclockwise from 0 degrees. In such a case, the radio wave does not reflect directly towards the receiver 21, and radio waves with sufficient intensity cannot reach the receiver 21.

[0099] However, according to the present embodiment, by making the reflecting surface 11d of the radio wave reflector 10 be a curved surface that bulges towards the side where the radio wave is incident or reflected, the radio wave reflector 10 can reflect radio waves with practical sufficient intensity within a relatively wide range in space. Therefore, even when the radio wave reflector 10 is installed at a position rotated from the position where it reflects the reflected wave directly towards the receiver 21, the receiver 21 can receive radio waves with practical intensity.

[0100] Regarding the radio wave reflector 10, the total light transmittance under a D65 standard light source (one of the standard light sources defined by the CIE (International Commission on Illumination)) is 65% or more, preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. The total light transmittance refers to the ratio of the total transmitted light beam to the parallel incident light beam of the test piece, as defined in JIS K7375:2008. That is, the radio wave reflector 10 is so-called "transparent", and "transparent" means that the other side can be seen with the naked eye when viewed from one side of the radio wave reflector 10, including translucent. In addition, the radio wave reflector 10 can be colored as a whole. In addition, as described in detail below, when the radio wave reflector 10 includes a base material layer 13, an adhesive layer 14, and a protective layer 15, each layer can be formed of a resin having a total light transmittance of 65% or more, and the conductor 12 of the conductive layer 16 can be formed to have a thickness with a total light transmittance of 65% or more.

[0101] In the present embodiment, as Figure 5 (A) shows, in a state where the radio wave reflecting material 11 (sheet-like member) before bending is placed on a plane, the overall shape of the radio wave reflecting material 11 (sheet-like member) is square in a top view, and preferably the length of one side is 20 cm or more and 400 cm or less. Radio waves with a frequency of 2 GHz or more and 300 GHz or less attenuate with distance. In all locations within the distance where the transmitter 20 can be actually used, in order to reflect with sufficient intensity, it is preferred that the length L10 of one side is 20 cm or more. The upper limit of the length L10 of one side is not particularly limited, and is preferably 400 cm or less from a manufacturing perspective. The overall shape is not limited to a square, and can be a rectangle, or a polygon such as a triangle, pentagon, or hexagon. In such a case, the length of the shortest side is set to 20 cm or more and 400 cm or less. Alternatively, the shortest distance between a certain vertex and the opposite side or the shortest distance between a certain side and the opposite side can be set to 20 cm or more and 400 cm or less. In addition, when the overall shape of the radio wave reflecting material 11 is circular, it is set to have a diameter of 20 cm or more and 400 cm or less. When the overall shape of the radio wave reflecting material 11 is elliptical, it is set to have a minor axis of 20 cm or more and 400 cm or less. When the overall shape of the radio wave reflecting material 11 is a sector, the length of the shorter one of the arc or the radius is set to 20 cm or more and 400 cm or less. In addition, the overall shape can be a three-dimensional shape such as a cylinder or a cone.

[0102] In order for the receiver 21 to receive radio waves with sufficient practical intensity, it is necessary to appropriately set the distance between the transmitter 20 and the radio wave reflection material 11, and the distance between the receiver 21 and the radio wave reflection material 11. In addition, the longer the wavelength of the radio waves reflected by the radio wave reflection material 11, that is, the smaller the frequency of the radio waves, the more necessary it is to increase the area of the reflection surface 11d of the radio wave reflection material 11. For example, when the frequency is less than 6 GHz, if the overall shape of the radio wave reflection material 11 (sheet-like member) is square in a top view, it is preferable to set the length of one side to 200 cm or less.

[0103] In this embodiment, the thickness L1 of the radio wave reflection material 11 is set to about 0.25 mm, but it is not limited thereto, and the thickness L1 is preferably 1 mm or less. Since the thickness L1 of the radio wave reflection material 11 is small, the conductor 12 has flexibility. Flexibility means having softness at normal temperature and pressure, and being able to deform such as flexing without undergoing shear or fracture even when a force is applied.

[0104] The surface resistivity of the radio wave reflection material 11 attached to a wall or the like and in a flat state is preferably 0.003 Ω / □ or more and 10 Ω / □ or less. As described in detail below, the surface resistivity is measured as the surface resistivity of the conductor 12. The surface resistivity of the radio wave reflection material 11 in a flat state refers to the surface resistivity of the radio wave reflection material 11 when it is placed on a flat mounting surface. "Plane" means a surface on which, for any two points on the surface, the straight line connecting them always lies.

[0105] Surface resistivity means the surface resistance per 1 cm 2 (1 square centimeter). The surface resistivity can be measured by the four-terminal method based on JIS K6911 by bringing test terminals into contact with the surface of the conductive layer 16 below. It should be noted that when protection is implemented with a resin sheet or the like and the conductive layer 16 is not exposed, a non-contact resistance measuring device (manufactured by NAPSON Corporation, trade name: EC-80P or its equivalent) can be used to measure by the eddy current method.

[0106] The radio wave reflection material 11 can have plasticity. Plasticity means being able to deform by applying an external pressure, and when a deformation exceeding the elastic limit is imparted by pressurization, maintaining the deformed shape even when the force is removed. All of the synthetic resins constituting the base material layer 13, the adhesive layer 14, and the protective layer 15 can have plasticity, or at least one of the base material layer 13, the adhesive layer 14, and the protective layer 15 can have plasticity.

[0107] (Structure of the radio wave reflection material 11)

[0108] An example of the structure of the radio wave reflecting material 11 will be described with reference to Figure 4 , Figure 5 . It should be noted that Figure 4 , Figure 5 (A) is a view of the radio wave reflecting material 11 (sheet-like member) before bending placed on a plane. The radio wave reflecting material 11 may have a conductive layer 16 including a conductor 12, a base material layer 13 including a base material holding the conductive layer 16, a protective layer 15 including a protective material for protecting the conductive layer 16, and an adhesive layer 14 including an adhesive material for bonding the conductive layer 16 and the protective layer 15. In Figure 4 , the radio wave reflecting material 11 is laminated in the order of the base material layer 13, the conductive layer 16, the adhesive layer 14, and the protective layer 15 from below.

[0109] It should be noted that in the description of the structure of the radio wave reflecting material 11, the up-down direction is defined based on Figure 4 , and the horizontal and vertical directions and the left-right direction are defined based on Figure 5 , Figure 6 . However, the up-down direction, the horizontal and vertical directions, and the left-right direction are used for explanation and do not define the up-down direction, the horizontal and vertical directions when the radio wave reflecting material 11 is installed in a building or the like. In addition, Figures 1 to 11 does not represent an actual scale. In addition, in Figure 5 (A), the illustration of the adhesive layer 14 and the protective layer 15 is omitted as it is a part of the radio wave reflecting material 11.

[0110] (Base material layer 13)

[0111] The base material layer 13 holds the conductors 12 in an array state on the upper surface and is made of a base material. In the present embodiment, the outer shape is formed as a square in a top view, but it is not limited thereto, and it may be a rectangle, a circle, an ellipse, a sector, a polygon, a three-dimensional shape, etc. according to the overall shape of the radio wave reflecting material 11. As the base material of the base material layer 13, a sheet made of a synthetic resin is used. As the synthetic resin, for example, one or more selected from PET (polyethylene terephthalate), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyester, polyoxymethylene, polyamide, polyphenylene ether, vinylidene chloride, polyvinyl acetate, polyvinyl acetal, AS resin, ABS resin, acrylic resin, fluororesin, nylon resin, polyacetal resin, polycarbonate resin, polyamide resin, and polyurethane resin can be mentioned. In addition, the thickness L2 of the base material layer 13 ( Figure 4 the length in the up-down direction in

[0112] (Conductive layer 16)

[0113] Regarding the conductive layer 16, preferably one or more linear conductors 12 are formed as a thin film on the upper surface of the base material layer 13. The conductor 12 is preferably made of silver (Ag), for example. It should be noted that the conductor 12 may be made of a metal having free electrons and is not limited to silver. For example, it may also be gold, copper, platinum, aluminum, titanium, silicon, indium tin oxide, and alloys (such as alloys containing nickel, chromium, and molybdenum). As alloys containing nickel, chromium, and molybdenum, for example, various grades such as Hastelloy B-2, B-3, C-4, C-2000, C-22, C-276, G-30, N, W, and X can be cited.

[0114] In addition, the thickness (film thickness) L3 of the conductive layer 16 (conductor 12) is 500 nm (0.5 μm) in the present embodiment, but is not limited thereto. From the viewpoint of ensuring appropriate radio wave intensity, the thickness L3 is preferably 5 nm or more. It should be noted that the conductive layer 16 may contain substances such as arbitrary synthetic resins and arbitrary components in addition to the conductor 12.

[0115] The surface resistivity of the conductive layer 16 is preferably 3.5 Ω / square or less. Regarding the surface resistivity of the conductive layer 16, it is the surface resistivity of the radio wave reflection material 11.

[0116] In one example, regarding the conductive layer 16, one or more linear conductors 12 are arranged to surround the region 12a without the conductor 12. That is, the conductor 12 and the region 12a without the conductor 12 surrounded by the conductor 12 are periodically arranged at a given interval. The interval between adjacent regions 12a without the conductor 12 may be a length equal to the line width L6 of the conductor 12 or a length longer than the line width L6. It should be noted that "linear" means that the length in the length direction is 3000 times or more the length in the direction orthogonal to the length direction. Regarding the arrangement pattern of the conductor 12 in the present embodiment, for example, as Figure 5As shown in (B), the conductors 12 are arranged at equal intervals in the longitudinal and transverse directions, and the region 12a without conductors 12 surrounded by the conductors 12 is square. That is, the regions 12a without conductors 12 are arranged at intervals of the line width L6 of the conductors 12. At the intersection where the conductor 12 (12A) in the transverse direction coincides with the conductor 12 (12B) in the longitudinal direction, the conductors 12A and 12B are electrically connected. The line width L6 of the conductor 12 is set to be 0.1 μm or more and 4.0 μm or less. The length L7 between adjacent conductors 12 in the longitudinal or transverse direction (the length of one side of the square region 12a without conductors 12) is set to be longer than the wavelength of visible light and shorter than the wavelength of the radio wave reflected by the radio wave reflection material 11. In the present embodiment, it is set to be 2 μm or more and 10 cm or less. More preferably, it is 20 μm or more and 1 cm or less, and still more preferably, it is 25 μm or more and 1 mm or less. Further preferably, it is 30 μm or more and 250 μm or less.

[0117] The arrangement pattern of the conductor 12 is not limited to Figure 5 the arrangement shown in (B). For example, the intervals between adjacent conductors 12A extending in the transverse direction are different from the intervals between adjacent conductors 12B extending in the longitudinal direction, and the shape of the region 12a without conductors 12 may be rectangular.

[0118] In addition, the conductor 12 can be arranged in the arrangement pattern shown in Figure 6 (A) to (E). In Figure 6 (A), the arrangement of the conductor 12 is a brick-stacking pattern. A plurality of first linear bodies 12A are arranged in the transverse direction and at a given interval in the longitudinal direction. Between adjacent first linear bodies 12A in the longitudinal direction, a plurality of second linear bodies 12B extending in the longitudinal direction are arranged in a staggered manner. The staggered manner means that a plurality of second linear bodies 12B extending in the longitudinal direction are arranged at a given interval in the transverse direction, and the plurality of second linear bodies 12B forming a column are located between the plurality of second linear bodies 12B in the columns adjacent in the longitudinal direction forming the column, and the second linear bodies 12B in the columns skipping one column are arranged in a straight line. The region 12a without conductors 12 is a region surrounded by two adjacent first linear bodies 12A and two adjacent second linear bodies 12B.

[0119] In Figure 6In (B), the conductor 12 is arranged such that the region 12a without the conductor 12 is triangular. As the region 12a without the conductor 12, there are provided a plurality of triangular first regions 12b and a plurality of inverted triangular second regions 12c. The first regions 12b and the second regions 12c are arranged at regular intervals in the horizontal and vertical directions respectively, and the second regions 12c are arranged between adjacent first regions 12b. The first region 12b and the second region 12c are regions surrounded by the first to third linear bodies 12A to 12C respectively. The first linear body 12A is arranged along the horizontal direction, the second linear body 12B is arranged along a direction inclined with respect to the first linear body 12A, and the third linear body 12C is arranged along a direction symmetric to the first linear body 12A with respect to the second linear body 12B.

[0120] It should be noted that in Figure 6 of (B), the shapes of the regions 12b and 12c may be equilateral triangles, or may be isosceles triangles or triangles with different side lengths.

[0121] In Figure 6 (C), the conductor 12 is arranged so as to surround the region 12a without the conductor 12 which is a regular hexagon. The regions 12a without the conductor 12 are arranged continuously at intervals of the line width L6 of the conductor 12 in the vertical direction, and a plurality of such columns are arranged in the horizontal direction. Between the regions 12a without the conductor 12 adjacent in the vertical direction, the regions 12a without the conductor 12 of the columns adjacent in the horizontal direction are arranged.

[0122] In Figure 6 (D), as the region 12a without the conductor 12, there are provided a plurality of regions 12b to 12d with different shapes. The region 12a without the conductor 12 includes a first region 12b which is a regular pentagon surrounded by a linear conductor 12, a second region 12c which is an inverted regular pentagon, and a third region 12d which is a rhombus. The first region 12b to the third region 12d are arranged at regular intervals in the horizontal and vertical directions respectively. Specifically, the first region 12b and the second region 12c are arranged such that they are adjacent in the vertical direction at an interval of the line width L6 of the conductor 12, and the group of the first region 12b and the second region 12c is arranged in the horizontal direction and periodically. The third region 12d is arranged between the groups of the first region 12b and the second region 12c adjacent in the horizontal direction. The shapes formed by the first region 12b, the second region 12c, and the third region 12d are arranged with the same period.

[0123] In Figure 6(E), as the region 12a without the conductor 12, has a variety of regions 12b to 12d without the conductor 12 with different shapes. The region 12a without the conductor 12 includes a circular first region 12b surrounded by a linear conductor 12, a substantially triangular second region 12c, and a substantially inverted triangular third region 12d. The first to third regions 12b to 12d are periodically arranged at regular intervals in the longitudinal and transverse directions. The first region 12b is arranged and periodically configured in the transverse and inclined directions in a continuous manner at an interval of the line width L6 of the conductor 12.

[0124] It should be noted that Figure 6 (A) to (E) only illustrate the conductor 12. In addition, the constitution of the conductor 12 other than the configuration pattern, such as the thickness L3, the line width L6, and the type of metal of the conductor 12, can also be set in the same manner as Figure 5 (B).

[0125] The conductive layer 16 preferably has a conductor coverage rate of 1% or more and 10% or less. The conductor coverage rate refers to the proportion of the area occupied by the conductor 12 in the unit area in the top view. The coverage rate can also be the proportion of the area of the substrate layer 13 covered by the conductor 12 relative to the area of the substrate layer 13 in the top view. As in the embodiment shown in Figure 4 , Figure 5 , when the conductive layer 16 is not provided at the outer periphery of the substrate layer 13 but is provided inside the edge of the substrate layer 13, the coverage rate refers to the proportion of the area occupied by the conductor 12 in the unit area in the region where the conductive layer 16 is provided on the upper surface of the substrate layer 13 in the top view. The region where the conductive layer 16 is provided refers to the region obtained by removing the outer periphery of the substrate layer 13 (the portion between the edge of the substrate layer 13 and the conductive layer 16) from the upper surface region of the substrate layer 13. The conductor coverage rate is measured by a scanning electron microscope (SEM), a transmission electron microscope (TEM), an optical microscope, etc.

[0126] As a method for manufacturing the conductive layer 16 having the above-described configuration pattern, there is a method of forming a pattern by etching after forming a conductor film and taking out a conductive thin film body having the pattern. In addition, there can be mentioned a method of coating a photosensitive resist on a base film provided with a release layer, forming a pattern by photolithography, filling the pattern portion with a conductor, and then taking out a conductive thin film body having the pattern, etc.

[0127] (Other embodiments of the conductive layer 16)

[0128] The conductor 12 constituting the conductive layer 16 can be, for example, Figure 7In the manner shown. The conductor 12 is formed by overlapping a first conductive portion 62 including a plurality of first enclosing portions 61 and a second conductive portion 64 including a plurality of second enclosing portions 63 in a pattern. When the first enclosing portion 61 and the second enclosing portion 63 are projected onto parallel projection planes of the conductive layer 16, they do not have a common part with each other.

[0129] Regarding the first conductive portion 62, the first enclosing portions 61 that enclose a first region AR1 where the conductor 12 is not formed are repeatedly formed at a constant pitch. Here, the first conductive portion 62 is formed in a grid pattern, and may also be formed in a pentagonal shape, a hexagonal shape, a circular shape, etc.

[0130] The second conductive portion 64 encloses a fourth region AR4 which is a region where the conductor 12 is not formed. The fourth region AR4 is formed in a manner that straddles a plurality of adjacent first regions AR1. The second conductive portion 64 may be located in the same plane as the first conductive portion 62, or may be located in a different plane. That is, the second conductive portion 64 may be conductive or non-conductive with respect to the first conductive portion 62. In addition, adjacent second conductive portions 64 are separated from each other, and may also be in contact. It should be noted that the second conductive portion 64 is formed in a quadrilateral shape, and may also be formed in a pentagonal shape, a hexagonal shape, a circular shape, etc.

[0131] The conductor 12 may also be, for example, in the manner as Figure 8 shown. Figure 8 Compared with the manner of Figure 7 , the shape of the second conductive portion 64 (the second enclosing portion 63) is different, and the second enclosing portion 63 is circular. The center points of the second enclosing portions 63 are arranged in a manner that overlaps the intersections of the first conductive portion 62 formed in a grid pattern, and the diameter of the second enclosing portion 63 is equal to the grid pitch of the first conductive portion 62. That is, adjacent second enclosing portions 63 are in contact with each other. It should be noted that adjacent second enclosing portions 63 may also be separated from each other. Other configurations are the same as those in the manner of Figure 6 , so the corresponding configurations are denoted by the same reference numerals and the description is omitted.

[0132] (Adhesive layer 14)

[0133] Regarding the adhesive layer 14, it is an adhesive layer that bonds the protective layer 15 on the substrate layer 13 and the conductive layer 16, and is composed of an adhesive material. The adhesive layer 14 has a size adapted to the substrate layer 13 in a top view. As the adhesive material of the adhesive layer 14, a synthetic resin or a rubber adhesive sheet is used. As the synthetic resin, for example, acrylic resin, silicone resin, polyvinyl alcohol resin, etc. can be cited. The thickness L4 of the adhesive layer 14 is set to 150 μm in the present embodiment, but is not limited thereto. It should be noted that the adhesive layer 14 not only includes the adhesive material, but may also include any substances such as synthetic resins, any components.

[0134] The adhesive layer 14 preferably uses a substance containing a synthetic resin material with a dielectric loss tangent (tanδ) of 0.018 or less. The lower the dielectric loss tangent, the more preferred, and it is usually 0.0001 or more. The dielectric loss tangent is a value indicating the degree of electrical energy loss in a dielectric. The greater the dielectric loss tangent of a material, the greater the electrical energy loss. By using the adhesive layer 14 with a dielectric loss tangent of 0.018 or less, the electrical energy loss of the radio wave in the radio wave reflection material 11 becomes smaller, and the reflection intensity becomes stronger.

[0135] In addition, the synthetic resin material of the adhesive layer 14 is preferably a material whose relative dielectric constant changes according to the frequency of the electric field. The relative dielectric constant is the ratio of the dielectric constant of a dielectric (the synthetic resin material in this embodiment) to the dielectric constant of a vacuum. By changing the relative dielectric constant according to the electric field, the intensity of the reflected wave of the electric field at a specific frequency can be increased. The relative dielectric constant preferably varies between 1.5 and 7. More preferably, it varies between 1.8 and 6.5. The dielectric loss tangent and the relative dielectric constant are measured by known methods (such as the cavity resonator method and the coaxial resonator method) using a measuring device (for example, TOYO Corporation, model TTPX desktop cryogenic probe station, material impedance analyzer MIA-5M).

[0136] It should be noted that not only the adhesive layer 14, but also the synthetic resin materials constituting the base material layer 13 and the protective layer 15 can be materials with a dielectric loss tangent of 0.018 or less, or materials whose relative dielectric constant changes according to the electric field.

[0137] In addition, the adhesive layer 14 preferably has a hydroxyl value of 5 mgKOH / g or more, more preferably 8 mgKOH / g or more, further preferably 30 mgKOH / g or more, and further preferably 90 mgKOH / g or more. On the other hand, the upper limit of the hydroxyl value of the adhesive layer 14 is preferably 120 mgKOH / g or less. When the hydroxyl value of the adhesive layer 14 is 5 mgKOH / g or more, the adhesive layer 14 has the advantages of being less likely to foam or / and turn white in a high-temperature and high-humidity environment. In this specification, the hydroxyl value is measured by a test method based on JIS K 1557.

[0138] In addition, the acid value of the adhesive layer 14 is preferably 50 mgKOH / g or less, more preferably 45 mgKOH / g or less, further preferably 30 mgKOH / g or less, and still further preferably 10 mgKOH / g or less. On the other hand, the lower limit of the acid value of the adhesive layer 14 is preferably 0.1 mgKOH / g or more. When the acid value of the adhesive layer 14 is 50 mgKOH / g or less, corrosion of the conductor 12 can be prevented, and the stability of the radio wave reflectivity over time can be improved. In this specification, the acid value is measured by a test method based on JIS K 2501.

[0139] The adhesive layer 14 preferably does not contain an ultraviolet absorber. When the adhesive layer 14 does not contain an ultraviolet absorber, the adhesive layer has the advantage of being easily adjusted to be colorless and transparent. Here, "does not contain" includes not only the case where the ultraviolet absorber is not contained at all, but also the case where the adhesive layer 14 contains a trace amount that does not impair colorless transparency.

[0140] (Protective layer 15)

[0141] Regarding the protective layer 15, in a plan view, it has a size corresponding to the base material layer 13, protects the conductor 12, and is made of a protective material. As the protective material of the protective layer 15, a film made of a synthetic resin is used. Examples of the synthetic resin include one or more selected from PET (polyethylene terephthalate), COP (cycloolefin polymer), polyethylene, polypropylene, polyvinyl chloride, polystyrene, polymethyl methacrylate, polyester, polyoxymethylene, polyamide, polyphenylene ether, vinylidene chloride, polyvinyl acetate, polyvinyl acetal, AS resin, ABS resin, acrylic resin, fluororesin, nylon resin, polyacetal resin, polycarbonate resin, polyamide resin, and polyurethane resin. The thickness L5 of the protective layer 15 is set to 50 μm in this embodiment, but is not limited thereto. It should be noted that the protective layer 15 includes not only the protective material but also any synthetic resin and other substances and any components.

[0142] Regarding the protective layer 15, for example, on at least one of the upper surface (outer surface) and the lower surface (surface in contact with the adhesive layer 14) of the synthetic resin film Figure 4 anti-glare treatment or anti-reflection treatment can be performed.

[0143] The anti-glare treatment (also referred to as "AG treatment", "non-glare treatment") means a treatment in which an uneven shape is formed on at least one surface of the protective layer 15 to scatter light and suppress the entry of light sources such as lighting into the protective layer 15. As a method for performing the anti-glare treatment, for example, a method of coating an adhesive resin in which fine particles are dispersed on the surface of the film can be cited. In addition, known methods such as sandblasting and chemical etching can be used.

[0144] Anti-reflection treatment (also referred to as "AR treatment") means forming an anti-reflection film on at least one surface of a film, causing the reflected light reflected from the surface of the anti-reflection film and the reflected light reflected from the interface between the anti-reflection film and the film to be attenuated by interference, and suppressing the ingress of light sources such as illumination. The anti-reflection film can be a single layer or obtained by alternately laminating thin films with different refractive indices, using known anti-reflection films.

[0145] Regarding the protective layer 15, it can be obtained by attaching a film that has been subjected to anti-glare treatment or anti-reflection treatment to one or both surfaces of a synthetic resin film.

[0146] Regarding the protective layer 15, the water vapor permeability at a temperature of 40°C and a humidity of 90% rh (relative humidity) is preferably 20 g / m 2 ·24 h or less, more preferably 16 g / m 2 ·24 h or less, further preferably 12 g / m 2 ·24 h or less, even more preferably 10 g / m 2 ·24 h or less. When the water vapor permeability of the protective layer 15 at a temperature of 40°C and a humidity of 90% rh (relative humidity) is 20 g / m 2 ·24 h or less, there are advantages such as the conductive layer 16 not being easily corroded and the surface resistivity of the conductive layer 16 not being easily increased. The so-called "water vapor permeability" in this specification is measured by a test method based on JIS Z 0208 (1976).

[0147] (Other embodiments of the configuration of the radio wave reflection material 11)

[0148] As Figure 9 shown in other embodiments of the present invention. It should be noted that Figure 9 is a view of the state in which the radio wave reflection material 11 (sheet-like member) before bending is placed on a plane. Regarding Figure 9 the radio wave reflection material 11 shown, the conductive layers 16A and 16B are laminated in two layers in the up and down direction. The arrangement patterns of the conductive layer 16A formed on the base material layer 13A and the conductive layer 16B formed on the base material layer 13B are aligned in an overlapping manner when viewed from above. It should be noted that the arrangement patterns of the conductive layers 16A and 16B may not overlap in the top view, and the conductive layers 16A and 16B may be formed with different arrangement patterns. Above the conductive layer 16A, the lower surface of the base material layer 13B is attached through the adhesive layer 14A, and above the conductive layer 16B, the protective layer 15 is attached through the adhesive layer 14B.

[0149] The radio wave incident on the radio wave reflection material 11 is reflected by the conductive layer 16B of the first layer, and a part of it passes through the conductive layer 16B without being reflected by the conductive layer 16B. The radio wave that has passed through the conductive layer 16B is reflected by the conductive layer 16A of the second layer. Thus, by stacking a plurality of conductive layers 16 including the conductor 12 in the vertical direction, the radio wave that has passed through the upper conductive layer 16B can be reflected by the lower conductive layer 16A, and the reflection intensity of the radio wave reflection material 11 can be maintained larger compared with the case where the conductor 12 is only one layer. In addition, by using two adhesive layers 14A and 14B, the value of the tangent of the dielectric loss angle can be made smaller further compared with the Figure 4 embodiment shown, and the reflection intensity can be maintained larger. The other configurations and operations are the same as those of the Figure 4 , Figure 5 embodiment shown, so the corresponding components are denoted by the same reference numerals and detailed descriptions are omitted.

[0150] It should be noted that, Figure 9 in the embodiment of, the conductive layer 16 formed on the base material layer 13 is stacked in two layers, and may also be stacked in three or more layers. When the number of stacked conductive layers 16 increases, the reflection intensity increases, and the thickness of the entire radio wave reflection material 11 becomes thicker, so the total light transmittance and flexibility are reduced. Therefore, the number of stacked conductive layers 16 is appropriately set according to the use purpose and the like.

[0151] (Other embodiments of the configuration of the radio wave reflection material 11)

[0152] Figure 10 Other embodiments of the radio wave reflection material 11 are shown. It should be noted that, Figure 10 is a view of the radio wave reflection material 11 (sheet-like member) before bending placed on a plane. In the Figure 10 embodiment, the radio wave reflection material 11 includes a conductive layer 16 and a base material layer 13, and does not include an adhesive layer 14 and a protective layer 15. In the above case, the conductor 12 of the conductive layer 16 forms a square-shaped thin film as a sheet on substantially the entire upper surface of the base material layer 13. The thickness L3 of the conductor 12 is set to 10 nm in this embodiment, but is not limited thereto. The surface resistivity is 9.8 Ω / square in this embodiment. In the Figure 10 embodiment, with respect to the conductor coverage rate, it is defined as the ratio of the area occupied by the conductor 12 in the unit area in the portion where the conductive layer 16 is provided on the base material layer 13, and the conductor coverage rate is 100%. In this embodiment, the total light transmittance of the radio wave reflection material 11 is 70%. The other configurations and operations are the same as those of the Figure 4 , Figure 5 embodiment shown, so the corresponding components are denoted by the same reference numerals and detailed descriptions are omitted.

[0153] It should be noted that in this embodiment, the conductive layer 16 is composed of one conductive body 12, or may be composed of multiple conductive bodies 12. In such a case, the multiple conductive bodies 12 are arranged at a given interval on substantially the entire surface of the upper surface of the base material layer 13. In addition, the shape of the conductive body 12 can be circular, rectangular, triangular, polygonal, etc.

[0154] (Use)

[0155] The radio wave reflector 10 including any of the above radio wave reflection materials 11 can also be included in the building material 30 and used. Regarding the building material 30, for example, as Figure 11 (A) shows, as decorative materials 30A such as wall surfaces, ceiling surfaces, floor surfaces of indoor and corridors, wallpapers for partition walls, posters, etc., and decorative materials 30B such as transparent seals for lamp shades, they are materials that can be installed in a building. For example, by installing the decorative materials 30A and 30B including the radio wave reflector 10 on the wall surface 31 and the lamp shade 32, the radio waves that enter the room from outside through the window 33, etc. are reflected by the decorative materials 30A and 30B provided on the wall surface 31 and the lamp shade 32. Thereby, the radio waves reach a wider range of the indoor space S, improving the convenience of radio wave reception.

[0156] In addition, the radio wave reflector 10 can be formed as a substance held inside the building material 30. For example, the wall surface 31 itself and the lamp shade 32 itself of the building material 30 can also be composed of the radio wave reflector 10. In addition, the building material 30 is not limited to indoor walls and lamp shades, and can also be partition walls, columns, lintels, outer walls of buildings, windows, etc. For example, Figure 11 (B) is a view obtained by observing the interior from above. The building material 30 as the radio wave reflector 10 is formed as a corner column 30C having a curved surface at the corner of the room. The radio waves entering from the window 33 are reflected on the corner column 30C, enabling the radio waves to reach a wider range of the indoor space S. It should be noted that Figure 11 (A), Figure 11 (B) shows application examples of the building material 30 and does not represent the actual range of radio wave reflection. In addition, the radio wave reflector 10 is not limited to the building material 30 and can be held inside a component made of a non-conductive material such as resin and used at any position.

[0157] (Evaluation test)

[0158] As the radio wave reflector 10, Preparation Examples 1 to 10 and Comparative Examples 1 and 2 were prepared. In these Preparation Examples 1 to 10 and Comparative Examples 1 and 2, an evaluation test on the reception intensity of the receiver 21 was conducted. However, the radio wave reflector 10 of the present invention is not limited to Preparation Examples 1 to 10.

[0159] (Evaluation Test A)

[0160] (Examples 1 to 4, Comparative Example 1)

[0161] As Figure 5 (A) shows, the radio wave reflector 10 of Examples 1 to 4 is a sheet-like member having a square planar shape with a side length L10 of 40 cm and a thickness L1 of 0.25 mm before being mounted on the object to be mounted 24. The sheet-like member is bent such that the vertex 11c of the convex shape is located at the center in the left-right direction and the lateral edges 11b in the up-down direction of the radio wave reflecting material 11 (sheet-like member) are close to each other, and is formed into the shape shown in Figure 2 (A), Figure 2 (B). That is, as Figure 2 (A) shows, the cross-sectional shape of the radio wave reflector 10 along the imaginary plane including the incident direction and the reflection direction is semi-circular, and is a shape convex toward the side where radio waves are incident or reflected.

[0162] The width L11 of the bottom and the curvature of the reflection surface 11d of Examples 1 to 4 are as follows.

[0163] (1) Example 1

[0164] Width of bottom L11 (cm): 39.8

[0165] Curvature 1 / r (1 / m): 0.87

[0166] (2) Example 2

[0167] Width of bottom L11 (cm): 35.0

[0168] Curvature 1 / r (1 / m): 2.21

[0169] (3) Example 3

[0170] Width of bottom L11 (cm): 30.0

[0171] Curvature 1 / r (1 / m): 3.19

[0172] (4) Example 4

[0173] Width of bottom L11 (cm): 20.0

[0174] Curvature 1 / r (1 / m): 4.73

[0175] In Comparative Example 1, it is a sheet-like member having a square planar shape with a side length L10 of 40 cm and a thickness L1 of 0.25 mm, and does not have a convex reflection surface 11d, and the reflection surface 11d is a flat surface. That is, it is Figure 5The sheet-like component shown in (A), which can also be said to be the radio wave reflector 10 before bending.

[0176] The other configurations of Examples 1 to 4 and Comparative Example 1 are as described below. It should be noted that Examples 1 to 4 and Comparative Example 1 have the same configuration unless otherwise specified. Therefore, only Example 1 will be described below, and the descriptions of Examples 2 to 4 and Comparative Example 1 will be omitted.

[0177] The radio wave reflecting material 11 of the radio wave reflector 10 prepared in Example 1 has a conductive layer 16, a base material layer 13, a protective layer 15, and an adhesive layer 14 containing an adhesive material for bonding the conductive layer 16 and the protective layer 15, and is laminated in the order of the base material layer 13, the conductive layer 16, the adhesive layer 14, and the protective layer 15 from below. It should be noted that the thickness L1 of the radio wave reflecting material 11 is the sum of the thickness L3 of the conductive layer 16, the thickness L2 of the base material layer 13, the thickness L4 of the adhesive layer 14, and the thickness L5 of the protective layer 15. However, the thickness L3 of the conductive layer 16 is very thin compared to the respective thicknesses L2, L4, and L5 of the base material layer 13, the adhesive layer 14, and the protective layer 15. Therefore, the thickness L3 of the conductive layer 16 is not considered in the thickness L1 of the radio wave reflecting material 11.

[0178] A synthetic resin material sheet (manufactured by TORAY INDUSTRIES, INC., LUMIRROR 50T60) made of PET is used as the base material layer 13, and the thickness L2 of the base material layer 13 is 50 μm.

[0179] The conductor 12 of the conductive layer 16 is a linear metal thin film containing silver (Ag), the thickness (film thickness) L3 is 500 nm, the line width L6 is 0.5 μm, and the length L7 between adjacent conductors 12 is 60 μm. The surface resistivity of the conductive layer 16 is 1.7 Ω / □, and the conductor coverage rate is 3.3%.

[0180] As the adhesive layer 14, a rubber-based adhesive is used. Specifically, for the adhesive layer 14, 100 parts by weight of a rubber-based polymer (a mixture of 50% by mass of styrene-(ethylene-propylene)-styrene block copolymer and 50% by mass of styrene-(ethylene-propylene) block copolymer, styrene content 15%, weight average molecular weight 130,000), 40 parts by weight of a synthetic resin (manufactured by Mitsui Chemicals, Inc., FMR-0150), 20 parts by weight of a softening agent (manufactured by JX Nippon Oil&Energy Corporation, LV-100), 0.5 parts by weight of an antioxidant (manufactured by ADEKA CORPORATION, ADK STAB AO-330), and 150 parts by weight of toluene are added to a reaction vessel equipped with a condenser tube, a nitrogen introduction tube, a thermometer, a dropping funnel, and a stirring device, and stirred at 40 °C for 5 hours. The thickness L4 of the adhesive layer 14 is 150 μm. The dielectric loss tangent of the adhesive layer 14 is 0.04.

[0181] A synthetic resin film (manufactured by Toray Industries, Inc., LUMIRROR 50T60) made of PET is used as the protective layer 15. The thickness L5 of the protective layer 15 is 50 μm.

[0182] It should be noted that with respect to the thickness L1 of the radio wave reflecting material 11, the thickness L3 of the conductive layer 16, the thickness L2 of the base material layer 13, the thickness L4 of the adhesive layer 14, and the thickness L5 of the protective layer 15, multiple arbitrary positions are measured, and the average value of the measured values obtained by calculation is used. For the measurement of the thicknesses L1 to L5, for example, a reflectance spectroscopic film thickness measuring instrument (e.g., F3-CS-NIR manufactured by FILMETRICS, Inc.) is used as the measuring instrument.

[0183] The manufacturing method of the radio wave reflecting material 11 of Example 1 will be described. First, the conductor 12 is formed on the base material layer 13. On one surface of a copper foil having a thickness of 5 to 200 μm with sufficient strength as a metal layer, a core layer of 0.01 to 3 μm is formed by methods such as electrolytic or electroless plating. Then, a conductive layer 16 with a given configuration pattern is formed on the surface of the core layer by methods such as electrolytic or electroless plating. Next, the entire conductive layer 16 is covered with the base material layer 13. An adhesive is previously coated on the base material layer 13. Then, the copper foil and the core layer are etched away. Thus, the conductor 12 is formed on the base material layer 13.

[0184] Then, the protective layer 15 is attached to the side of the conductor 12 opposite to the base material layer 13 through the adhesive layer 14. The adhesive layer 14 is used to attach the protective layer 15 to the conductor 12 on the base material layer 13 in such a way that no bubbles enter. Thus, the radio wave reflecting material 11 is manufactured.

[0185] Regarding the surface resistivity, in the state where the conductive layer 16 is formed and exposed during the manufacturing of Example 1, Comparative Example 1, and Comparative Example 2, the test terminals are brought into contact with the surface of the conductive layer 16, and the measurement is performed by the four-terminal method based on JIS K6911.

[0186] (Radio wave reflection system 100)

[0187] The radio wave reflection system 100 used in Evaluation Test A will be described. The radio wave reflection system 100 includes a transmitter 20, a receiver 21, and a rotational position adjusting device 50. As Figure 12As shown, a support plate 51 is mounted on a rotational position adjusting device 50 (also referred to as "rotary table 50"), and the radio wave reflectors 10 of Examples 1 to 4 and Comparative Example 1 (hereinafter also referred to as "samples") are mounted on the support plate 51. The side edge 11b of the radio wave reflector 10 is fixed to the support plate 51 in such a manner that the vertex 11c of the radio wave reflector 10 is located at the center of rotation of the rotary table 50 in a top view. The transmitter 20 and the receiver 21 are fixed at a position corresponding to the central position in the length in the vertical direction of the radio wave reflector 10. That is, the transmitter 20, the receiver 21, and the vertex 11c located at the center in the vertical direction of the radio wave reflector 10 are arranged on the same plane. This plane is a plane including the incident direction and the reflection direction of the radio wave. On this plane, the normal reflection angle is 60 degrees, the distance between the vertex 11c of the radio wave reflector 10 and the transmitter 20 is set to 4 m, and the distance between the vertex 11c of the radio wave reflector 10 and the receiver 21 is set to 6 m.

[0188] A rectangular horn antenna is used as the receiver 21 (receiving antenna), and a spectrum analyzer (MS2760A manufactured by Anritsu Corporation) is connected to the receiver 21. An amplifier is interposed between the receiver 21 and the spectrum analyzer. A radio wave with a frequency of 60 GHz is output from the transmitter 20, and the reception intensity based on the receiver 21 is measured. It should be noted that the receiving antenna is not limited to a rectangular horn antenna, and other directional antennas such as dipole antennas or non-directional antennas such as omnidirectional antennas can also be used.

[0189] (Method for measuring reception intensity)

[0190] The method for measuring the reception intensity (reception power) of the sample by the receiver 21 is as follows. In a top view, the radio wave reflector 10 is rotated about the vertex 11c of the radio wave reflector 10. The position of the radio wave reflector 10 when the radio wave is normally reflected is set as the rotation angle to be 0 degrees, and the radio wave reflector 10 is rotated at 1-degree intervals within the range from -90 degrees to +90 degrees, and the reception intensity of the receiver 21 is measured at each rotation angle . It should be noted that the + direction refers to Figure 12 the clockwise direction in Figure 12 , and the - direction refers to

[0191] (Evaluation index)

[0192] As an evaluation index, at each rotation angle of the radio wave reflector 10, the reception intensity (reception power) received by the receiver 21 is measured, and the rotation angle of the radio wave reflector 10 at which the receiver 21 can receive the radio wave with a practical intensity, that is, an intensity of -95 dB or more, is obtained.range.

[0193] (Evaluation result)

[0194] Figures 13 to 17 Indicates the measurement result. Figure 13 Is the result of Comparative Example 1. In the range where the rotation angle of the radio wave reflector 10 Is from about -15 degrees to about +15 degrees, the receiver 21 receives radio waves with an intensity of -95 dB or more.

[0195] Figure 14 Is the result of Example 1. In the range where the rotation angle of the radio wave reflector 10 Is from about -25 degrees to about +15 degrees, the receiver 21 receives radio waves with an intensity of -95 dB or more. Figure 15 Is the result of Example 2. In the range where the rotation angle of the radio wave reflector 10 Is from about -50 degrees to about +35 degrees, the receiver 21 receives radio waves with an intensity of -95 dB or more. Figure 16 Is the result of Example 3. In the range where the rotation angle of the radio wave reflector 10 Is from about -45 degrees to about +60 degrees, the receiver 21 receives radio waves with an intensity of -95 dB or more. Figure 17 Is the result of Example 4. In the range where the rotation angle of the radio wave reflector 10 Is from about -83 degrees to about +83 degrees, the receiver 21 receives radio waves with an intensity of -95 dB or more.

[0196] Thus, compared with the flat sheet-like radio wave reflector 10 without a convex shape in Comparative Example 1, the receiver 21 of the radio wave reflector 10 with a convex shape in Examples 1 to 4 can receive radio waves with a practical and sufficient intensity at a larger range of rotation angles Therefore, even if the radio wave reflector 10 is installed at a position rotating within a given range of rotation angles centered on the vertex 11c, the receiver 21 can receive radio waves with a practical intensity. In addition, in Examples 1 to 4, the smaller the width L11 of the bottom, that is, the greater the curvature, the larger the range of rotation angles at which the receiver 21 can receive radio waves with a practical and sufficient intensity.

[0197] The applicant found that by making the reflecting surface 11d of the radio wave reflector 10 convex, compared with the case where the reflecting surface 11d of the radio wave reflector 10 is a flat surface, the radio wave reflector 10 can reflect radio waves with a practical and sufficient intensity in a wider range in space. Therefore, even if the radio wave reflector 10 is installed at a position rotating within a given range of rotation angles centered on the vertex 11c, the receiver 21 can receive radio waves with a practical intensity.

[0198] (Evaluation Test B)

[0199] (Examples 5 - 10)

[0200] In Evaluation Test B, Examples 5 - 10 used are sheet-like components with a rectangular planar shape, longitudinal and lateral dimensions of 539 mm × 485 mm, and a thickness L1 of 0.16 mm in the state before being installed on the object to be installed 24. The width L11 at the bottom and the value of the curvature 1 / r are as follows.

[0201] (5) Example 5

[0202] Width L11 of the bottom (mm): 482

[0203] Curvature 1 / r (1 / m): 0.792

[0204] (6) Example 6

[0205] Width L11 of the bottom (mm): 462

[0206] Curvature 1 / r (1 / m): 2.23

[0207] (7) Example 7

[0208] Width L11 of the bottom (mm): 438

[0209] Curvature 1 / r (1 / m): 3.24

[0210] (8) Example 8

[0211] Width L11 of the bottom (mm): 385

[0212] Curvature 1 / r (1 / m): 4.75

[0213] (9) Example 9

[0214] Width L11 of the bottom (mm): 365

[0215] Curvature 1 / r (1 / m): 5.25

[0216] (10) Example 10

[0217] Width L11 of the bottom (mm): 243

[0218] Curvature 1 / r (1 / m): 7.81

[0219] In Examples 5 to 10, the conductor 12 of the conductive layer 16 is a linear metal thin film made of copper (Cu), with a thickness (film thickness) L3 of 1.6 μm, a line width L6 of 2.4 μm, and a length L7 between adjacent conductors 12 of 100 μm. The surface resistivity of the conductive layer 16 is 0.7 Ω / square, and the conductor coverage rate is 7%. The other configurations are the same as those in Example 1, so the description is omitted.

[0220] In Comparative Example 2, a sheet-like component with a rectangular planar shape and longitudinal and lateral dimensions of 539 mm × 485 mm. The other configurations are the same as those in Comparative Example 1, so the description is omitted.

[0221] (Radio wave reflection system 110)

[0222] The radio wave reflection system 110 used in Evaluation Test B will be described. As Figure 18 shown, the radio wave reflection system 110 includes a transmitter 20, a receiver 21, and a moving mechanism (not shown) for the receiver 21. The frequency of the radio waves transmitted by the transmitter 20 is 2 GHz or more and 300 GHz or less. The radio wave reflector 10 is set and fixed so as to protrude toward the incident direction and the reflection direction side of the radio waves and does not rotate. The transmitter 20 and the receiver 21 are arranged at positions corresponding to the central position of the length in the vertical direction of the radio wave reflector 10. That is, the transmitter 20, the receiver 21, and the vertex 11c located at the center in the vertical direction of the radio wave reflector 10 are arranged on the same plane. This plane is the plane including the incident direction and the reflection direction of the radio waves. On this plane, the transmitter 20 is arranged on the normal line 22 of the vertex 11c of the radio wave reflector 10. The distance between the vertex 11c and the transmitter 20 is set to 1.0 m. The receiver 21 can move on a virtual circumference centered on the vertex 11c with a radius equal to the distance between the vertex 11c and the transmitter 20 through the moving mechanism. The other configurations of the radio wave reflection system 110 are the same as those of the radio wave reflection system 100 used in Evaluation Test A.

[0223] (Method for measuring received intensity)

[0224] The method for measuring the received intensity (received power) of the sample by the receiver 21 is as follows. In a top view, the position of the receiver 20 is changed. When the receiver 21 is located on the normal line 22 of the vertex 11c of the radio wave reflector 10 on the said plane, the rotation angle of the receiver 21 is set to 0 degrees, and the receiver 21 is rotated at 15-degree intervals within the range from -75 degrees to +75 degrees, and the received intensity of the receiver 21 is measured at the position of each rotation angle . It should be noted that the + direction refers to Figure 18 the counterclockwise direction in Figure 18in the clockwise direction. Regarding the radio wave transmitted to the sample, the output from the transmitter 20 is 1 mW.

[0225] (Evaluation index)

[0226] Relative to Examples 5 to 10 and Comparative Example 2, the rotation angle of the receiver 21 is changed as described above, and the received intensity (received power) received by the receiver 21 is measured. The frequencies of the radio waves transmitted to the sample are 4.85 GHz and 28 GHz.

[0227] The evaluation is carried out as follows. Calculate the absolute value of the difference between the reflection intensity at normal reflection (i.e., the rotation angle is 0 degrees) and the reflection intensities at other rotation angles Extract the rotation angles whose absolute value of the difference does not exceed 10 dB. The extracted rotation angles change from positive values to negative values. Calculate the absolute value of the maximum value and the absolute value of the minimum value of the values of the extracted rotation angles and select the smaller absolute value. Calculate the value obtained by adding a positive value to the absolute value and the value obtained by adding a negative value to the absolute value, and set the difference value as the angular range (unit: degree) of the rotation angle at which the receiver 21 can receive radio waves with sufficient received intensity.

[0228] For example, in the case of Example 5 shown in Table 1, as the rotation angle is 0 degrees, the rotation angles whose absolute value of the difference between the reflection intensity and the reflection intensities at other rotation angles does not exceed 10 dB are extracted as -30 degrees, -15 degrees, +15 degrees, +30 degrees, and +45 degrees. The maximum value of the extracted rotation angles is 45, the minimum value is -30, and the absolute values are 45 and 30. Therefore, the smaller 30 is selected. Moreover, the value obtained by adding a positive value to the absolute value is +30, the value obtained by adding a negative value to the absolute value is -30, and 60 as the difference is set as the angular range (unit: degree) of the rotation angle at which the receiver 21 can receive radio waves with sufficient received intensity.

[0229] When the angular range is 150 degrees or more, it is evaluated as "◎", when the angular range is 120 degrees or more and less than 150 degrees, it is evaluated as "○", when the angular range is 60 degrees or more and less than 120 degrees, it is evaluated as "△", and when the angular range is less than 60 degrees, it is evaluated as "×". If the evaluation is "◎", "○", or "△", the radio wave reflector 10 can reflect radio waves with practical sufficient intensity within a sufficiently wide angular range.

[0230] Table 1 and Table 2 show the relationship between the rotation angle of the receiver 21​​​ Measurement results of received intensity and evaluation of angular range. Figure 19 and Figure 20 Indicates the measurement results of received intensity. In Tables 1 and 2, the shaded range represents the rotation angle at which the receiver 21 can receive radio waves with sufficient received intensity. of the angular range. Figure 19 Table 1 shows the results when the frequency of the radio wave is 4.85 GHz. Figure 20 Table 2 shows the results when the frequency of the radio wave is 28 GHz. Compared with the flat radio wave reflector 10 of Comparative Example 2 in Examples 5 to 10, the angular range at which the receiver 21 can receive radio waves with sufficient received intensity is expanded compared to the case of specular reflection. Thus, even when the receiver 21 is disposed at a position deviated from the specular reflection direction of the radio wave, the radio wave reflector 10 can sufficiently reflect radio waves of practical intensity. In addition, when the curvature of the radio wave reflector 10 increases, the angular range at which the receiver 21 can receive radio waves with sufficient received intensity increases.

[0231] [Table 1]

[0232] Table 1 Frequency of radio wave 4.85 GHz

[0233]

[0234] [Table 2]

[0235] Table 2 Frequency of radio wave 28 GHz

[0236]

[0237] The above describes one embodiment of the present invention. The present invention is not limited to the described embodiment, and various modifications can be made as long as the gist of the present invention is not departed from. Regarding the dimensions, materials, shapes, and relative configurations of the constituent elements described in the embodiments or shown in the drawings, it is not the gist of limiting the scope of the present invention thereto, but only illustrative examples. For example, in expressions indicating relative or absolute configurations such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial", it does not strictly represent only such configurations, but also represents a state of relative displacement with tolerances or at an angle or distance that achieves the same function. For example, in expressions indicating a state where things such as "the same", "equal", and "homogeneous" are equal, it does not strictly represent only an equal state, but also represents a state where there are tolerances or differences that achieve the same function. For example, in expressions indicating shapes such as a quadrilateral shape or a cylindrical shape, it does not represent only the shapes of a quadrilateral shape or a cylindrical shape in a strictly geometric sense, but also represents shapes including concavo-convex portions, chamfered portions, etc. within the range of achieving the same effect. In expressions such as "comprising", "having", "including", or "containing" a constituent element, it is not an exclusive expression excluding the existence of other constituent elements.

[0238] Symbol Explanation

[0239] 10 Radio wave reflector

[0240] 11 Radio wave reflection material

[0241] 11b Side edge

[0242] 11c Vertex of convex shape

[0243] 12 Conductor

[0244] 13 Base material layer

[0245] 14 Adhesive layer

[0246] 15 Protective layer

[0247] 16 Conductive layer

[0248] 20 Transmitter

[0249] 21 Receiver

[0250] 24 Object to be installed

[0251] 40 Holding member

[0252] 50 Rotation position adjusting device (rotary table)

[0253] 100 Radio wave reflection system

[0254] 101 Radio wave reflection structure

[0255] 102 Radio wave reflection device

[0256] L6 Line width of the conductor

[0257] L10 Length of one side of the radio wave reflector

[0258] L11 Width of the bottom of the radio wave reflector

[0259] Rotation angle

Claims

1. A radio wave reflector having a reflecting surface for reflecting radio waves, wherein the reflecting surface is a curved surface convex toward the side where radio waves are incident or reflected.

2. The radio wave reflector according to claim 1, wherein the curvature 1 / r of the reflecting surface satisfies 0 (1 / m) < 1 / r ≤ 7.85 (1 / m).

3. The radio wave reflector according to claim 1, wherein the curvature 1 / r of the reflecting surface satisfies 5.00 (1 / m) < 1 / r ≤ 7.85 (1 / m).

4. The radio wave reflector according to any one of claims 1 to 3, comprising: a conductive layer containing a conductor and forming the reflecting surface; a base material layer containing a base material for holding the conductive layer; a protective layer containing a protective material for protecting the conductive layer; and an adhesive layer containing an adhesive material for bonding the conductive layer and the layer containing the protective material, wherein the radio wave reflector is laminated in the order of the base material layer, the conductive layer, the adhesive layer, and the protective layer.

5. The radio wave reflector according to claim 4, wherein the flexural modulus is 0.05 GPa or more and 4 GPa or less.

6. The radio wave reflector according to any one of claims 1 to 5, further comprising a holding member for holding the reflecting surface.

7. A method for manufacturing the radio wave reflector according to any one of claims 1 to 5, comprising: a step of bending the reflecting surface into a curved surface convex toward the side where radio waves are incident or reflected when installing on an object to be installed.

8. A method for manufacturing the radio wave reflector according to claim 6, comprising: a step of holding, by the holding member, the curved surface of the reflecting surface convex toward the side where radio waves are incident or reflected before installing on an object to be installed.

9. A radio wave reflection structure, comprising: the radio wave reflector according to any one of claims 1 to 6; and an object to be installed on which the radio wave reflector is installed.

10. A radio wave reflection system, comprising: a transmitter for transmitting radio waves; the radio wave reflector according to any one of claims 1 to 6, which reflects the radio waves transmitted from the transmitter; a receiver for receiving the radio waves reflected by the radio wave reflector; and a rotational position adjusting device provided on the radio wave reflector for rotating the radio wave reflector.

11. The radio wave reflection system according to claim 10, wherein the rotational position adjusting device rotates the radio wave reflector around the vertex of the convex portion of the radio wave reflector when viewed from a plane parallel to the plane including the incident direction and the reflection direction of radio waves on the reflecting surface, when the rotation angle of the position of the radio wave reflector at the time of directly reflecting the radio waves transmitted from the transmitter to the receiver is set to 0 degrees, the clockwise rotation direction is set as the + direction, and the counterclockwise rotation direction is set as the - direction, the position of the radio wave reflector that can be adjusted by the rotational position adjusting device is within the range of -90 degrees or more and +90 degrees or less in terms of rotation angle.

12. The radio wave reflection system according to claim 11, wherein the curvature 1 / r is 4.73 (1 / m), When the radio wave reflector is located at a position within the range of rotation angles of -83 degrees or more and +83 degrees or less, the receiver receives radio waves of -95 dB or more.

13. A radio wave reflection device, comprising: the radio wave reflector according to any one of claims 1 to 6; and a rotational position adjusting device that is provided on the radio wave reflector and rotates the radio wave reflector.

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